| 摘要 |
The invention refers to a method for data transmission in a local are network, wherein data is transmitted on the MAC layer within successive time frames (SF) between a plurality of first nodes (N1, N2, ..., N7) being client nodes to a second node (N8) being a coordinator node for the first nodes (N1, N2, ..., N7). The method of the invention uses a specific structure for the time frames (SF), where a synchronising slot (BS) for sending a synchronising message (B) from the second node (N8) to the first nodes (N1, N2, ..., N7) includes acknowledgements (A1, A2) for time slots (S1, S2, ..., Sn; R1, R2, ..., Rm) used for data transmissions in previous time frames from the first nodes (N1, N2, ..., N7) to the second node (N8). Those acknowledgements indicate whether a data transmission in the previous time frame was successful or not. Based on those acknowledgements (A1, A2), retransmission time slots (R1, R2, ..., Rm) included in the current time frame (SF) are used for retransmitting data which have not been transmitted successfully in a time slot (S1, S2, ..., Sn; R1, R2, ..., Rm) of the previous time frame. The method of the invention enables a data transmission in the MAC layer with low packet loss rates and a low number of changes in the transmission direction between the first nodes (N1, N2, ..., N7) and the second node (N8). Preferably, the method of the invention is used in combination with the standard IEEE 802.15.4 being adapted for data transmissions in wireless sensor and actuator networks. |
